Method for recovering tellurium from tellurium anode slime

Abstract

The invention discloses a method for recovering tellurium from tellurium anode slime, and belongs to the technical field of chemical engineering, tellurium in the tellurium anode slime is recovered by preparing mesoporous manganese dioxide / lignin-based carbon spheres with a circulating effect, and lignin is converted into a carbon sphere carrier, so that sustainable utilization of resources is realized, expensive raw materials of traditional carbon materials are replaced, and the method is suitable for industrial production. The preparation cost of the adsorbent is greatly reduced, and the recovery rate of tellurium is improved; according to the mesoporous manganese dioxide / lignin-based carbon sphere, lignin is used as a carbon sphere carrier, silicon dioxide is used as a template, a mesoporous structure is formed, manganese dioxide is loaded on the surface, a mesoporous and micropore composite structure is formed, the large aperture of mesopores is similar, tellurium ions or fine tellurium particles in a leaching system can rapidly penetrate through the surface of a material and enter internal pores, and meanwhile, the tellurium ions or the fine tellurium particles can rapidly penetrate through the surface of the material. Mesopores can also reduce the retention resistance of the leachate in pores, so that the target substance of tellurium can be ensured to be in continuous contact with internal adsorption sites, and the loss of tellurium along with leaching residues caused by slow mass transfer is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical industry, and particularly relates to a method for recovering tellurium from tellurium anode slime. BACKGROUND

[0002] The anode slime generated in the tellurium electrolysis process is mainly sodium tellurate, and other impurities have a low content, the formation reason and existing form of which are complex, the main component of the anode slime is sodium tellurate, oxygen is generated at the anode in the electrolysis process, and the electrolyte is.

[0003] The tellurate is difficult to dissolve in alkaline liquor, is precipitated to form a crystal nucleus in the electrolytic cell, is dispersed near the anode plate or is attached to the anode plate and gradually grows to form particles, and is settled to the bottom of the cell due to the gravity; a part of the tellurate is attached to the wall of the cell and grows; and a small amount of the tellurate is attached to the surface of the cathode plate and is mostly returned to the electrolyte or a small amount of the tellurate is still retained as the tellurium is continuously precipitated and the electrolyte is circulated and washed. If the particles formed on the cathode are not cleaned for a long time, the particles are wrapped in the tellurium sheet, the cleaning work is not only large in workload but also is easy to affect the quality of the tellurium sheet. Since the tellurium content of the sodium tellurate generated in the electrolytic refining process accounts for 3-20% of the total tellurium content, the electrolysis needs to be cleaned regularly and the tellurium in the anode slime needs to be recovered, so that the quality of the tellurium sheet is ensured and the tellurium recovery rate is improved, which has great significance for resource comprehensive utilization and reduction of production cost.

[0004] Chinese patent 201610310326.3 discloses a method for recovering and recycling tellurium from tellurium anode slime, and the technical scheme is that the tellurium anode slime is washed with distilled water, the uncleaned Na2TeO3 is oxidized with hydrogen peroxide, then dilute sulfuric acid is slowly added to the tellurium anode slime to leach tellurium, a tellurium leaching solution is obtained by filtration, the tellurium leaching solution is reduced to crude tellurium powder with Na2SO3, the crude tellurium powder is dissolved with nitric acid solution, the solution is neutralized with waste liquid discharged periodically by tellurium electrodeposition or tellurium anode slime washing water, the reaction end point pH value is controlled, the tellurium is completely converted into tellurium dioxide, and impurities are removed from the solution after neutralization.

[0005] However, the hydrogen peroxide has insufficient oxidation capacity and is easy to fail, the stability of the hydrogen peroxide is poor under acidic conditions, the hydrogen peroxide is easy to decompose, the hydrogen peroxide cannot continuously oxidize low-valence tellurium, and the oxidation selectivity of the hydrogen peroxide is low, the hydrogen peroxide may preferentially react with impurities in the anode slime, and the oxidation efficiency of the hydrogen peroxide on the tellurium is further reduced. SUMMARY

[0006] The purpose of the present application is to provide a method for recovering tellurium from tellurium anode slime, the method recovers the tellurium in the tellurium anode slime by preparing mesoporous manganese dioxide / lignin-based carbon spheres with a recycling effect, and converts lignin into a carbon sphere carrier, so that the sustainable utilization of resources is realized, the expensive raw materials of traditional carbon materials are replaced, the preparation cost of the adsorbent is greatly reduced, and the recovery rate of the tellurium is improved.

[0007] The object of the present application can be achieved by the following technical solutions: A method for recovering tellurium from tellurium anode slime, comprising the following steps: The crude tellurium powder and the nitric acid solution with a mass fraction of 25-30% are placed in a stainless steel reaction kettle, and are stirred and dissolved at 20-25 DEG C and 500-600 r / min for 10-12 min, the generated gas is absorbed by an acid mist absorption tower and then is exhausted, the anode slime washing water and the tellurium electrodeposition waste liquid are pumped into the reaction kettle for neutralization, the pH value is controlled to be 5-6, and filtration and washing are carried out, so that the tellurium dioxide is obtained; the tellurium dioxide is dissolved by the tellurium electrodeposition waste liquid, sodium sulfide with a concentration of 1 g / L is further added for purification and filtration to remove impurities, so that the refined tellurium is obtained, and the method for recovering tellurium from the tellurium anode slime is completed.

[0008] Further, the crude tellurium powder is prepared by the following steps: The anode slime produced by tellurium electrodeposition is placed in a stainless steel reaction kettle, is washed by distilled water for 3-4 times, is separated by filtration to obtain anode slime washing water, and is stored for use; mesoporous manganese dioxide / lignin-based carbon balls are added into the filter residue, stirring is carried out at 70-80 DEG C and 120-140 r / min for 2-3 h, then dilute sulfuric acid is added for leaching for 3-4 h, the leaching end point pH value is controlled to be 1.5-2, after leaching is completed, filtration is carried out, the filtrate is heated to 80-85 DEG C, and sodium sulfonate is added to continue stirring reaction for 6-7 h, and then filtration is carried out, so that the crude tellurium powder is obtained.

[0009] Further, the use amount ratio of the anode slime, the mesoporous manganese dioxide / lignin-based carbon balls and the dilute sulfuric acid is 120-130 kg:2.4-2.6 kg:20-22 L.

[0010] Further, the mesoporous manganese dioxide / lignin-based carbon balls are prepared by the following steps: The silica / manganese dioxide nanoparticles, the lignin-based carbon balls and the sodium carbonate solution with a concentration of 3 mol / L are added into a reaction kettle, stirring is carried out at 20-25 DEG C and 500-600 r / min for 13-14 h, centrifugation is carried out at 14000-15000 r / min for 15-20 min, the precipitate is washed by deionized water and anhydrous ethanol for 2-4 times respectively, and vacuum drying is carried out at 60-70 DEG C for 1-2 h, so that the mesoporous manganese dioxide / lignin-based carbon balls are obtained.

[0011] Further, the use amount ratio of the silica / manganese dioxide nanoparticles, the lignin-based carbon balls and the sodium carbonate solution is 18-20 kg:13-14 kg:15-16 L.

[0012] Further, the silica / manganese dioxide nanoparticles are prepared by the following steps: Potassium permanganate and deionized water are added into a reaction kettle, stirred at 20-25 DEG C and 500-600 r / min for 10-12 min, then silica particles with a particle size of 50-60 nm are added, ultrasonic stirring reaction is carried out for 7-8 h, centrifugation is carried out at 13000-14000 r / min for 20-30 min, filtration is carried out, the precipitate is washed with deionized water and anhydrous ethanol for 2-4 times respectively, and vacuum drying is carried out at 60-70 DEG C for 1-2 h, so as to obtain the silica / manganese dioxide nanoparticles.

[0013] Further, the use amount ratio of potassium permanganate, deionized water and silica particles is 24-25 kg: 16-17 L: 15-16 kg.

[0014] Further, the lignin-based carbon sphere is prepared by the following steps: Acetic acid and resin solution are added into a reaction kettle, stirred at 20-25 DEG C and 500-600 r / min for 10-12 min, then ferric chloride and deionized water are added, and stirring is continued for 1-2 h, flocculent precipitate is precipitated, standing is carried out for 30-35 min, centrifugation is carried out at 3500-3600 r / min for 10-12 min, filtration is carried out, the filter cake is placed in vacuum drying at 60-70 DEG C for 1-2 h, the product is transferred into a muffle furnace, heated to 350-360 DEG C under an argon atmosphere, and kept for 1-2 h, and then heated to 550-600 DEG C, and kept for 1-2 h, so as to obtain the lignin-based carbon sphere.

[0015] Further, the use amount ratio of acetic acid, resin solution, ferric chloride and deionized water is 10-12 kg: 5-6 L: 12-13 kg: 20-30 kg.

[0016] Further, the resin solution is prepared by the following steps: Lignosulfonic acid and deionized water are added into a reaction kettle, stirred at 20-25 DEG C and 500-600 r / min for 10-12 min, then polyvinyl alcohol is added, and stirring is continued for 15-20 min, then ammonia water and formaldehyde are added, heated to 45-50 DEG C, and kept for 24-26 h, then the temperature is continued to be raised to 100-110 DEG C, and kept for 20-24 h, 12-14 kg of epichlorohydrin is added dropwise and kept for 10-12 h, so as to obtain the resin solution.

[0017] Further, the use amount ratio of lignosulfonic acid, deionized water, polyvinyl alcohol, ammonia water and formaldehyde is 14-15 kg: 5-6 L: 12-14 kg: 13-14 kg: 7-8 L.

[0018] The beneficial effects of the present application are as follows: 1. The application provides a method for recovering tellurium from tellurium anode slime, which recovers tellurium in the tellurium anode slime by preparing mesoporous manganese dioxide / lignin-based carbon spheres with a recycling effect, and converts lignin into a carbon sphere carrier, realizes sustainable utilization of resources, replaces expensive raw materials of traditional carbon materials, greatly reduces the preparation cost of adsorbents, and improves the recovery rate of tellurium.

[0019] 2. The mesoporous manganese dioxide / lignin-based carbon spheres of the application use lignin as a carbon sphere carrier, silica as a template to form a mesoporous structure, and then load manganese dioxide on the surface to form a composite structure of mesopores and micropores. The large pore size of the mesopores can allow tellurium ions or small tellurium particles in the leaching system to quickly penetrate the material surface and enter the internal pores. At the same time, the mesopores can also reduce the residence resistance of the leaching solution in the pores, ensuring that the target material of tellurium can continuously contact the internal adsorption sites and avoiding the loss of tellurium with the leaching residue due to slow mass transfer.

[0020] 3. The tellurium in the tellurium anode slime is mainly in the form of low valence state. This form has very low solubility in the conventional leaching system and is easy to precipitate with the leaching residue, resulting in low leaching rate. The manganese dioxide loaded on the surface of the carbon spheres is a typical oxidizing agent, which can convert low valence tellurium into high solubility high valence tellurium form through oxidation reaction, thereby improving the leaching rate of tellurium. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the application will be described below in conjunction with the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the application.

[0022] Embodiment 1: A method for recovering tellurium from tellurium anode slime, comprising the following steps: S1: Put 14 kg of lignin sulfonic acid and 5 L of deionized water into a reaction kettle, stir at 20℃ and 500 r / min for 10 min, then add 12 kg of polyvinyl alcohol, continue to stir for 15 min, then add 13 kg of ammonia water and 7 L of formaldehyde, heat to 45℃, keep for 24 h, continue to heat to 100℃, keep for 20 h, and drop 12 kg of epoxy chloropropane and keep for 10 h to obtain a resin solution.

[0023] S2: 10 kg of acetic acid and 5 L of resin solution were added to the reaction kettle, stirred at 20℃ and 500 r / min for 10 min, then 12 kg of ferric chloride and 20 kg of deionized water were added, and the stirring was continued for 1 h, and a flocculent precipitate was separated out, and after standing for 30 min, it was centrifuged at 3500 r / min for 10 min, and then filtered, and the filter cake was vacuum dried at 60℃ for 1 h, and the product was transferred to a muffle furnace, heated to 350℃ under an argon atmosphere for 1 h, and then heated to 550℃ for 1 h, to obtain lignin-based carbon spheres.

[0024] S3: 24 kg of potassium permanganate and 16 L of deionized water were added to the reaction kettle, stirred at 20℃ and 500 r / min for 10 min, then 15 kg of silica particles with a particle size of 50 nm were added, and ultrasonic stirring was carried out for 7 h, and then centrifuged at 13000 r / min for 20 min, and filtered, and the precipitate was washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 60℃ for 1 h, to obtain silica / manganese dioxide nanoparticles.

[0025] S4: 18 kg of silica / manganese dioxide nanoparticles, 13 kg of lignin-based carbon spheres, and 15 L of a sodium carbonate solution with a concentration of 3 moL / L were added to the reaction kettle, stirred at 20℃ and 500 r / min for 13 h, and then centrifuged at 14000 r / min for 15 min, and the precipitate was washed with deionized water and anhydrous ethanol for 2 times respectively, and vacuum dried at 60℃ for 1 h, to obtain mesoporous manganese dioxide / lignin-based carbon spheres.

[0026] S5: 120 kg of anode sludge produced by tellurium electrodeposition was placed in a stainless steel reaction kettle, washed with distilled water for 3 times, and the anode sludge washing water was separated by filtration and stored for later use, 2.4 kg of mesoporous manganese dioxide / lignin-based carbon spheres were added to the filter residue, and stirred at 70℃ and 120 r / min for 2 h, then 20 L of dilute sulfuric acid was added for leaching for 3 h, and the leaching end point pH value was controlled at 1.5, after the leaching was completed, the filtrate was heated to 80℃, and sodium sulfonate was added for continuous stirring for 6 h, and then filtered, to obtain crude tellurium powder.

[0027] S6: The crude tellurium powder and a nitric acid solution with a mass fraction of 25% were placed in a stainless steel reaction kettle, stirred and dissolved at 20℃ and 500 r / min for 10 min, and the generated gas was discharged after being absorbed by an acid mist absorption tower, and the anode sludge washing water and tellurium electrodeposition waste liquid were pumped into the reaction kettle for neutralization, and the pH value was controlled at 5, and then filtered and washed, to obtain tellurium dioxide; the tellurium dioxide was dissolved with the tellurium electrodeposition waste liquid, and then impurities were removed by purification and filtration with sodium sulfide with a concentration of 1 g / L, to obtain refined tellurium, thereby completing the method for recovering tellurium from tellurium anode sludge.

[0028] Example 2: A method for recovering tellurium from tellurium anode sludge, comprising the following steps: S1: 14.5 kg of lignin sulfonic acid, 5.5 L of deionized water were added into a reaction kettle, stirred at 22.5℃ and 550 r / min for 11 min, then 13 kg of polyvinyl alcohol was added, and stirred for 17.5 min, then 13.5 kg of ammonia water and 7.5 L of formaldehyde were added, heated to 47.5℃, and kept for 25 h, then heated to 105℃, and kept for 22 h, then 13 kg of epichlorohydrin was added dropwise and kept for 11 h to obtain a resin solution.

[0029] S2: 11 kg of acetic acid and 5.5 L of the resin solution were added into a reaction kettle, stirred at 22.5℃ and 550 r / min for 11 min, then 12.5 kg of ferric chloride and 25 kg of deionized water were added, and stirred for 1.5 h, then a flocculent precipitate was separated, and stood for 32.5 min, then centrifuged at 3550 r / min for 11 min, filtered, and the filter cake was vacuum dried at 65℃ for 1.5 h, then the product was transferred to a muffle furnace, heated to 355℃ under an argon atmosphere, kept for 1.5 h, then heated to 575℃, kept for 1.5 h, and then lignin-based carbon spheres were obtained.

[0030] S3: 24.5 kg of potassium permanganate and 16.5 L of deionized water were added into a reaction kettle, stirred at 22.5℃ and 550 r / min for 11 min, then 15.5 kg of silica particles with a particle size of 55 nm were added, and ultrasonic stirring was performed for 7.5 h, then centrifuged at 13500 r / min for 25 min, filtered, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum dried at 65℃ for 1.5 h to obtain silica / manganese dioxide nanoparticles.

[0031] S4: 19 kg of silica / manganese dioxide nanoparticles, 13.5 kg of lignin-based carbon spheres, and 15.5 L of a sodium carbonate solution with a concentration of 3 moL / L were added into a reaction kettle, stirred at 22.5℃ and 550 r / min for 13.5 h, then centrifuged at 14500 r / min for 17.5 min, the precipitate was washed with deionized water and anhydrous ethanol for 3 times respectively, and vacuum dried at 65℃ for 1.5 h to obtain mesoporous manganese dioxide / lignin-based carbon spheres.

[0032] S5: 125 kg of anode sludge produced by tellurium electrodeposition was placed in a stainless steel reaction kettle, washed with distilled water for 3.5 times, and filtered to obtain anode sludge washing water, which was stored for later use, 2.5 kg of mesoporous manganese dioxide / lignin-based carbon spheres were added to the filter residue, stirred at 75℃ and 130 r / min for 2.5 h, then leached with 21 L of dilute sulfuric acid for 3.5 h, and the leaching end point pH value was controlled at 1.75, after leaching, the filtrate was heated to 82.5℃, and sodium sulfonate was added for stirring for 6.5 h, then filtered to obtain a crude tellurium powder.

[0033] S6: The crude tellurium powder and a mass fraction of 27.5% nitric acid solution are placed in a stainless steel reaction kettle, stirred at 22.5℃ and 550r / min for 11min, and the generated gas is absorbed by an acid mist absorption tower and then discharged. The anode slime washing water and tellurium electrowinning waste liquid are pumped into the reaction kettle for neutralization, and the pH value is controlled at 5.5. After filtration and washing, tellurium dioxide is obtained. The tellurium dioxide is dissolved with tellurium electrowinning waste liquid, and then impurities are removed by adding 1g / L sodium sulfide for purification and filtration to obtain refined tellurium, thereby completing the method for recovering tellurium from tellurium anode slime.

[0034] Example 3: A method for recovering tellurium from tellurium anode slime, comprising the following steps: S1: 15kg of lignin sulfonic acid and 6L of deionized water are added to a reaction kettle, stirred at 25℃ and 600r / min for 12min, then 14kg of polyvinyl alcohol is added, and stirring is continued for 20min. Then 14kg of ammonia water and 8L of formaldehyde are added, heated to 50℃, and kept for 26h. Continue to heat to 110℃ and keep for 24h. Add 14kg of epoxy chloropropane dropwise and keep for 12h to obtain a resin solution.

[0035] S2: 12kg of acetic acid and 6L of resin solution are added to a reaction kettle, stirred at 25℃ and 600r / min for 12min, then 13kg of ferric chloride and 30kg of deionized water are added, and stirring is continued for 2h. Flocculent precipitate is separated out, and after standing for 35min, centrifugation is carried out at 3600r / min for 12min. The filter cake is placed in a vacuum drying oven at 70℃ for 2h. The product is transferred to a muffle furnace, heated to 360℃ under an argon atmosphere, kept for 2h, and then heated to 600℃, kept for 2h to obtain lignin-based carbon spheres.

[0036] S3: 25kg of potassium permanganate and 17L of deionized water are added to a reaction kettle, stirred at 25℃ and 600r / min for 12min, then 16kg of silica particles with a particle size of 60nm are added, and ultrasonic stirring is carried out for 8h. Centrifugation is carried out at 14000r / min for 30min, and the precipitate is washed with deionized water and anhydrous ethanol for 4 times respectively, and vacuum dried at 70℃ for 2h to obtain silica / manganese dioxide nanoparticles.

[0037] S4: 20kg of silica / manganese dioxide nanoparticles, 14kg of lignin-based carbon spheres and 16L of 3moL / L sodium carbonate solution are added to a reaction kettle, stirred at 25℃ and 600r / min for 14h, and centrifugation is carried out at 15000r / min for 20min. The precipitate is washed with deionized water and anhydrous ethanol for 4 times respectively, and vacuum dried at 70℃ for 2h to obtain mesoporous manganese dioxide / lignin-based carbon spheres.

[0038] S5: 130 kg of tellurium anode slime produced by electrodeposition was placed in a stainless steel reaction kettle, washed with distilled water for 4 times, and filtered to separate the anode slime washing water for storage. 2.6 kg of mesoporous manganese dioxide / lignin-based carbon spheres were added to the residue, stirred at 80°C and 140 r / min for 3 h, then 22 L of dilute sulfuric acid was added and leached for 4 h, controlling the leaching end point pH value to be 2. After leaching, the filtrate was heated to 85°C, and sodium sulfonate was added for continuous stirring reaction for 7 h, and then filtered to obtain crude tellurium powder.

[0039] S6: The crude tellurium powder and a 30% mass fraction nitric acid solution were placed in a stainless steel reaction kettle and stirred at 25°C and 600 r / min for 12 min. The generated gas was absorbed by an acid mist absorption tower and then discharged. The anode slime washing water and tellurium electrodeposition waste liquid were pumped into the reaction kettle for neutralization, controlling the pH value to be 6, and then filtered and washed to obtain tellurium dioxide. The tellurium dioxide was dissolved with the tellurium electrodeposition waste liquid, and then impurities were removed by purifying and filtering with 1 g / L sodium sulfide to obtain refined tellurium, thereby completing the method for recovering tellurium from tellurium anode slime.

[0040] Comparative Example 1: On the basis of Example 3, the mesoporous manganese dioxide / lignin-based carbon spheres in step S5 were replaced by the silica / manganese dioxide nanoparticles prepared in step S3.

[0041] Comparative Example 2: On the basis of Example 3, the mesoporous manganese dioxide / lignin-based carbon spheres in step S5 were replaced by the lignin-based carbon spheres prepared in step S2.

[0042] Comparative Example 3: On the basis of Example 3, the lignin-based carbon spheres in step S4 were removed.

[0043] The potential was detected by a potentiometer, the tellurium content was detected by ICP, and the yield of tellurium was calculated.

[0044] The method for recovering tellurium provided in Examples 1-3 and Comparative Examples 1-3 was detected by a potentiometer, the tellurium content was detected by ICP, and the yield of tellurium was calculated, and the results are shown in Table 1: Table 1

[0045] The silica / manganese dioxide nanoparticles in Comparative Example 1 have the oxidation of manganese dioxide and the mesoporous template of silica, but lack the microporous structure of the lignin-based carbon spheres, the specific surface area is greatly reduced, the adsorption capacity is reduced, the lignin-based carbon spheres as the carrier are lacking, the silica / manganese dioxide nanoparticles are easy to agglomerate, the mesoporous structure is blocked, the mass transfer resistance of tellurium ions is increased, and the internal adsorption sites cannot be efficiently contacted; the surface functional groups of the lignin-based carbon spheres can assist in adsorbing tellurium ions, and after the lignin-based carbon spheres are removed, only the chemical adsorption of manganese dioxide is relied on, the double locking effect of tellurium disappears, and part of the tellurium ions are easy to flow out with the leaching residue, and the final yield is reduced.

[0046] The lignin-based carbon spheres in Comparative Example 2 have microporous structure and physical adsorption capacity, but lack the oxidation function of manganese dioxide, and cannot convert low-valence tellurium in anode sludge into high-valence tellurium with high solubility, the solubility of low-valence tellurium in dilute sulfuric acid leaching system is extremely low, even if the lignin-based carbon spheres have adsorption capacity, it is difficult to capture the undissolved solid tellurium particles, and a large amount of tellurium still remains in the leaching residue in the form of precipitate; only relying on physical adsorption cannot break through the bottleneck of tellurium dissolution, resulting in a large decrease in leaching rate and yield.

[0047] After the lignin-based carbon spheres are removed in Comparative Example 3, the silica / manganese dioxide nanoparticles lose the support of the carrier, are easy to disperse unevenly, and even fall off during the leaching and stirring process, and cannot stably play a role; without the microporous structure of the lignin-based carbon spheres, only the mesoporous formed by the silica template, the capture efficiency of tellurium is suddenly reduced, the loading of manganese dioxide loses the anchoring effect of the surface functional groups of the carbon spheres, the oxidation active sites are reduced, and the mesoporous structure is easy to collapse due to the lack of carbon sphere support, and finally neither low-valence tellurium can be efficiently oxidized nor tellurium ions can be effectively adsorbed, and the yield is reduced.

[0048] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and modifications can be made to these embodiments without departing from the principles and spirits of the present application.

Claims

1. A method for recovering tellurium from tellurium anode mud, characterized in that, Includes the following steps: Crude tellurium powder and a 25-30% nitric acid solution are placed in a stainless steel reactor and stirred for 10-12 minutes at 20-25℃ and 500-600 r / min. The generated gas is absorbed by an acid mist absorption tower and then discharged into the atmosphere. Anode mud wash water and tellurium electrodeposition waste liquid are pumped into the reactor for neutralization, and the pH value is controlled at 5-6. After filtration and washing, tellurium dioxide is obtained. Tellurium dioxide is dissolved in tellurium electrodeposition waste liquid, and then sodium sulfide at a concentration of 1 g / L is added for purification. After filtration to remove impurities, refined tellurium is obtained, thus completing the method for recovering tellurium from tellurium anode mud.

2. The method for recovering tellurium from tellurium anode mud according to claim 1, characterized in that, The coarse tellurium powder is prepared through the following steps: The anode mud produced by tellurium electrowinning is placed in a stainless steel reactor and washed 3-4 times with distilled water. The anode mud wash water is separated by filtration and stored for later use. Mesoporous manganese dioxide / lignin-based carbon balls are added to the filter residue and stirred at 70-80℃ and 120-140r / min for 2-3 hours. Then, dilute sulfuric acid is added for leaching for 3-4 hours, controlling the pH value at the leaching endpoint to be 1.5-2. After leaching is completed, the residue is filtered. The filtrate is heated to 80-85℃, sodium sulfonate is added, and the reaction is stirred for another 6-7 hours. After filtration, crude tellurium powder is obtained.

3. The method for recovering tellurium from tellurium anode mud according to claim 2, characterized in that, The ratio of anode mud, mesoporous manganese dioxide / lignin-based carbon spheres, and dilute sulfuric acid is 120-130 kg: 2.4-2.6 kg: 20-22 L.

4. The method for recovering tellurium from tellurium anode mud according to claim 1, characterized in that, The mesoporous manganese dioxide / lignin-based carbon spheres are prepared by the following steps: Silica / manganese dioxide nanoparticles, lignin-based carbon spheres, and a 3 mol / L sodium carbonate solution were added to a reaction vessel and stirred for 13-14 h at 20-25 °C and 500-600 r / min. The mixture was then centrifuged at 14000-15000 r / min for 15-20 min. The precipitate was washed 2-4 times with deionized water and anhydrous ethanol, respectively, and then vacuum dried at 60-70 °C for 1-2 h to obtain mesoporous manganese dioxide / lignin-based carbon spheres.

5. A method for recovering tellurium from tellurium anode mud according to claim 4, characterized in that, The ratio of silica / manganese dioxide nanoparticles, lignin-based carbon spheres, and sodium carbonate solution is 18-20 kg: 13-14 kg: 15-16 L.

6. The method for recovering tellurium from tellurium anode mud according to claim 1, characterized in that, The silica / manganese dioxide nanoparticles were prepared through the following steps: Potassium permanganate and deionized water were added to a reaction vessel and stirred for 10-12 min at 20-25℃ and 500-600 r / min. Then, silica particles with a particle size of 50-60 nm were added and the mixture was ultrasonically stirred for 7-8 h. After centrifugation at 13000-14000 r / min for 20-30 min, the mixture was filtered. The precipitate was washed 2-4 times with deionized water and anhydrous ethanol, respectively, and then vacuum dried at 60-70℃ for 1-2 h to obtain silica / manganese dioxide nanoparticles.

7. A method for recovering tellurium from tellurium anode mud according to claim 6, characterized in that, The ratio of potassium permanganate, deionized water, and silica particles is 24-25 kg: 16-17 L: 15-16 kg.

8. A method for recovering tellurium from tellurium anode mud according to claim 1, characterized in that, The lignin-based carbon spheres are prepared by the following steps: Acetic acid and resin solution were added to a reaction vessel and stirred for 10-12 min at 20-25℃ and 500-600 r / min. Then ferric chloride and deionized water were added and stirring was continued for 1-2 h to precipitate flocculent precipitate. The precipitate was allowed to stand for 30-35 min and then centrifuged at 3500-3600 r / min for 10-12 min. The precipitate was filtered and the filter cake was vacuum dried at 60-70℃ for 1-2 h. The product was then transferred to a muffle furnace and heated to 350-360℃ under an argon atmosphere for 1-2 h, and then heated to 550-600℃ for 1-2 h to obtain lignin-based carbon spheres. The ratio of acetic acid, resin solution, ferric chloride and deionized water is 10-12 kg: 5-6 L: 12-13 kg: 20-30 kg.

9. A method for recovering tellurium from tellurium anode mud according to claim 1, characterized in that, The resin solution is prepared by the following steps: Lignosulfonic acid and deionized water are added to a reaction vessel and stirred for 10-12 minutes at 20-25℃ and 500-600 r / min. Then polyvinyl alcohol is added and stirring is continued for 15-20 minutes. Ammonia and formaldehyde are then added, and the mixture is heated to 45-50℃ and kept at that temperature for 24-26 hours. The temperature is then increased to 100-110℃ and kept at that temperature for 20-24 hours. 12-14 kg of epichlorohydrin is added dropwise and kept at that temperature for 10-12 hours to obtain a resin solution.

10. A method for recovering tellurium from tellurium anode mud according to claim 9, characterized in that, The ratio of lignin sulfonic acid, deionized water, polyvinyl alcohol, ammonia, and formaldehyde is 14-15 kg: 5-6 L: 12-14 kg: 13-14 kg: 7-8 L.

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